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To investigate the effect and mechanism of plasma-activated water (PAW) on Aspergillus niger, PAW was prepared using a needle array–plate dielectric barrier discharge plasma system. The concentrations of long-lived reactive oxygen and nitrogen species (RONS), namely, H2O2, NO2−, and NO3−, in the PAW were 48.76 mg/L, 0.046 mg/L, and 172.36 mg/L, respectively. Chemically activated water (CAW) with the same concentration of long-lived RONS was also prepared for comparison. A. niger A32 was treated with PAW and CAW. After treatment, the treated strains were observed and analyzed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to screen probable mutants. The results indicated that the pH, conductivity, and ORP values of PAW were 2.42, 1935 μS/cm, and 517.07 mV, respectively. In contrast, the pH and ORP values of CAW were 6.15 and 301.73 mV, respectively, which differed significantly from those of PAW. In addition, the conductivity of CAW showed no change. SEM and TEM analyses revealed that A. niger A32 treated with CAW exhibited less damage compared with the control. In contrast, A. niger A32 treated with PAW showed significant shrinkage, deformation, and exudate attachment over time. Following PAW treatment, after four passages, a high cellulase-producing stable mutant strain A-WW5 was screened, exhibiting a filter paper enzyme activity of 29.66 U/mL, a cellulose endonuclease activity of 13.79 U/mL, and a β-glucosidase activity of 27.13 U/mL. These values were found to be 33%, 38%, and 2.1% higher than those of the original fungus sample, respectively. In total, 116 SNPs and 61 InDels were present in the genome of the mutant strain A-WW5. The above findings indicate that the impact of PAW on A. niger is not only attributed to long-lasting H2O2, NO2−, and NO3− particles but also to other short-lived active particles; PAW is expected to become a new microbial breeding mutagen. [ABSTRACT FROM AUTHOR]

High-voltage discharge plasma drying (HVDPD) is a non-thermal and efficient drying technique. In this study, we compared the drying characteristics and physicochemical properties of alfalfa dried via HVDPD, hot-air drying (HAD), and natural air-drying (AD) and analyzed the experimental results using infrared spectroscopy, scanning electron microscopy, colorimetry, and other detection techniques. The results showed that HVDPD had a higher drying rate than AD and saved more energy than HAD. Alfalfa dried via HVDPD had the most intact internal structure, the highest rehydration ratio (RR), the best color quality, and the best nutrient retention, resulting in the highest relative quality and feeding value. Therefore, HVDPD is an excellent drying technique for alfalfa, providing a new and effective way to improve the storage, transportation, and drying quality of alfalfa. [ABSTRACT FROM AUTHOR]

Exotic topological domains in BiFeO3 nanoislands have attracted much attention regarding their potential applications in advanced electronic devices. Here, different from the earlier reported disordered distributed BiFeO3 nanoislands formed by a self-assembly method, we fabricated an ordered BiFeO3 nanoisland array by mask-assisted pulsed laser deposition on a SrTiO3 substrate, which exhibits a center-converged in-plane polarization component and a monodomain pattern along the vertical direction. Such center-type quad-domain structures exhibit high stability, maintaining their topological structures after heating to 250 °C and subsequently cooling to room temperature. Moreover, they can be switched by applying a scanning electric field and recovered by applying a heating and cooling process. Observing this topological structure in BiFeO3 nanoislands might provide a suitable platform for further exploration of its topological phase transition properties, new functions, and potential applications. [ABSTRACT FROM AUTHOR]

Alfalfa seeds were directly treated with corona discharge plasma radiation and compared with the control group, which was covered by a Petri dish, blocking the etching effect of ionic wind and thus simulating the effect of a non-uniform electric field. The results showed that corona discharge plasma radiation changed the chemical structure of the seed coat. The peak value of the Fourier transform infrared spectrum of the seed coat at 2 856 cm‒1 and 1 729 cm‒1 changed after treatment, indicating that the wax, lipids, and cellulose in the seed coat may have been degraded. Measurements of the seed floating rate and apparent contact angle in the treated seeds compared to the measurements in the control group indicated that corona discharge plasma radiation also improved the hydrophilicity of the alfalfa seeds. In the control group, the Petri dish cover effectively reduced the physicochemical etching by ionic wind; thus, it appears that ionic wind has a greater influence on the seed coat than does the non-uniform electric field. Scanning electron micrograph images showed that the etching of the seed coat in the treated seeds was severe; the cellulose of the seed coat was degraded, and the surface was cracked, which improved the water absorption capacity of the seed. The seedling height of the seeds treated with corona discharge plasma radiation increased significantly compared to that of the control group, indicating that the physicochemical etching of the ionic wind had resulted in a macroscopic biological effect. This study provides experimental data support for the analysis of surface modification and chemical structure composition of alfalfa seeds treated with corona discharge plasma radiation and also provides a basis for further study of the biological effect mechanism of the corona discharge field.

Topological quad-domain textures in ferroelectric nanoislands have been considered as enablers for nanoelectric devices. However, the fabrication of ordered arrays of ferroelectric islands exhibiting this domain structure is a challenge. By using substrate patterning to create nucleation sites, highly ordered quad-domain ferroelectric polarization configurations were achieved in BiFeO3 nanoisland arrays. Reversible switching of the quad-domain between the center divergent state with highly conductive domain walls and the center convergent state with insulating domain walls can be realized, resulting in a resistance change with a large on/off ratio. This templated growth strategy enables the controllable fabrication of exotic topological domains and sheds light on their applications for configurable electronic devices. [ABSTRACT FROM AUTHOR]

In this study, the seeds of Medicago truncatula are treated with plasma and plasma‐activated water (PAW), and the RNA sequencing (RNA‐Seq) of the seedlings is performed to analyze the gene expression changes. It is found that plasma treatment has no significant effect on seed survival rate, but PAW has an obvious lethal effect. Both methods result in the differential expression of a large number of genes in seedlings, and the expression of genes with the function of promoting plant growth and metabolism is significantly upregulated. The roots of seedlings in PAW group grow lateral roots. This study provides new ideas and experimental evidence for PAW plant culture research and has a guiding significance for leguminous plant breeding. [ABSTRACT FROM AUTHOR]

In this study, a direct-current multineedle-plate corona discharge with different parameters was used to treat Ammopiptanthus mongolicus (Maxim. ex Kom. Cheng f.) seeds and study the effect of corona discharge physicochemical etching on these seeds. Results showed that the surface of the seed coat of A. mongolicus had wind erosion after corona discharge treatment, a large number of small ravines were generated and the surface crack of the seed coat was serious. Analysis of Fourier transform infrared spectroscopy revealed that the hydrophilic functional groups increased and corona discharge changed the chemical structure of A. mongolicus seed coat. The apparent contact angle decreased significantly from 99.82° ± 4.86° to 60.11° ± 8.44°, suggesting that corona discharge could significantly improve the hydrophilicity of A. mongolicus seeds. All the corona discharge treatment groups had seed germination at 24 h, whilst the control group had zero germination. This finding suggested that corona discharge treatment could significantly affect the structure and properties of A. mongolicus seed coat, improve the seed hydrophilicity and water absorption rate and promote the germination and growth of A. mongolicus seeds. This study provided ideas and experimental data support for the analysis of the mechanism of corona discharge biotechnology and seed-surface modification. [ABSTRACT FROM AUTHOR]